The present invention relates to an electric machine such as a motor or generator of the induction type.
A motor is an electromechanical device which converts electrical energy, delivered in the form of voltages or currents, into mechanical energy that is represented as rotational movement. One common type of motor consists of two major elements, a stator and a rotor. The stator typically includes a wire coil having a number of windings. The rotor typically includes permanent magnets. The rotor and stator are mechanically arranged such that the rotor can move freely with respect to the fixed stator. Electromagnetic interaction between the stator and rotor then causes the rotor to move for each polarity change in the stator windings. Other types of electric machines such as generators may be constructed in a similar fashion.
In one type of motor, the stator is formed by laminating a number of disks formed of a ferrous material to provide a cylindrical stator housing. The core disks have formed therein tabs or tines that provide a structure around which are wrapped bare copper wire strands to form the windings. The stator housing provides a coaxial located open space into which is inserted the rotor assembly. The rotor assembly typically is made from a number of electromagnets spaced about a shaft. Typically, the magnets are contained or held with the shaft by an outer sleeve. The rotor assembly is rotatably supported mechanically within the stator housing by low friction bearings.
Such motors have been widely accepted in industry for precision control applications, and they are presumably considered to perform reasonably well for their intended purpose. However, they are not without their shortcomings.
It would be desirable to eliminate the need to provide for a number of windings in the stator assembly from a manufacturing perspective.
It would also be desirable if the power generation or torque capability of a motor of a given size and weight could be increased.
Furthermore, the reliability of such motors could be improved, given that in extended use the wire windings of the rotors may sometimes tend to short or wear out.
The present invention is an electric machine, such as a brushless motor, in which the coil is formed by a set of electrically conductive blade structures disposed about an axis of a stator core. Electrical interconnections between the blades are provided by a set of disks mounted to the ends of the blades. The disks electrically connect the blades in a correct circuit orientation to provide a desired number of turns and phases for the machine.
The number of phases and number of turns associated with the motor may be changed by changing the circuit arrangement of the interconnect disks.
The non-conductive portions of the interconnect disks may be provided by a ceramic or other alumina material.
The blades and conductive portions of the interconnect disks are preferably formed from a material such as a copper and molybdenum laminate.
The outer layers of the blades may have a portion thereof which mechanically contacts a back iron structure of the stator assembly, to provide a rigid, rugged stator structure. In such a configuration, an insulating material is also formed along the blades to prevent the blades from shorting to the back iron.